GD&T by CADD.pdf

Reference Guideax ¢6.3-6.4 1$100.25®IAIB®1 ax LJ ¢9.4-9.6~ 5.6-6.0! 1$100.5®IAIB®1 II 0 070.0 II- -$ j_ 69.5 © D I ~ Look for the Authentic CADD Centre Genuine Hologram! CADD® CENTRE Driving Digital Designs! L MrlMs: Centre: PrOduct: Month & Year : @;"tyFlrSI o r/ CADD Centre is the leader in CAD / CAE / PPM training for over 2 decades through regular technology upgrades and striving to deliver quality to its valued customers. CADD Centre instructors are trained and certified at regular intervals to ensure their technical competency and delivery standards. The certified instructors of our centres reassure the quality of training to our customers. To know more, write to: [email protected] Corporate Office: #91, Office No: 8C & 80, 8'h Floor, GEEGEECrystal, Dr. Radhakrishnan Salai, CADD® Mylapore, Chennai - 600 004. CENTRE Ph : 044 - 4596 6100 Driving Digital Designsl /. • .t (/ ~t," EXIN Electronic Desi n Automation S stem Administration • ITIL Foundation • Foundation Courses • Professional Course on System • Foundation for Green IT Citizen • Diploma Courses Administration • Green IT Foundation • Professional in EDA • Professional Course on IT • Cloud Computing Administration • Master Diploma in EDA • ISO/IEC20000 • Foundation Course on System • Bridge based on ISO/IEC20000 • Real-time Application Training Administration • ISO/IEC27002 • MCTIP Enterprise Administrator • LlNUX Courses Network Engineering IT Administration • Professional in Network Security • Professional Course on IT • Foundation Course on Network Administration • PPM Concepts Engineering • Network Engineering • CCNA Routers & Switches • System Administration • CCNA Network Security www.livewireindia.com Email: [email protected] PEARSON :J<IN CompTiA cad e n ce' VUE-Authorised Test Centre LIVEWlre™ FOR LIVE CAREERS co.in Skillease Where High-End Talent Matters .in Somewhere in this world. and you won't remain one for long. it's 5killease.skillease. Forward your resume today to jobs@skULease. Dedicated to provide staffing solutions to corporate majors.co. 50 register with us as a job-seeker. is a place meant for you. Our job is to help you get there.www. this is the place that bridges the world of talent with the world of requirement. If it's talent. Geometric Dimensioning and Tolerancing CADD® CENTRE . in whole or in part. transmitted. Editor CURRICULUM AND PRODUCT DEVELOPMENT TEAM We appreciate your valuable feedback/suggestion on this courseware. . electronic. 2016 All Rights Reserved This publication. transcribed. manual or otherwise. Copyright © CADD Centre Training Services Private Limited May. CCTSPLV332052016 1 ..com r .f'{' . stored in a retrieval system or translated into any language or computer language in any form or by any means. photographic. or parts thereof. Kindly do mail it to us at: cpd@caddcentre.. . mechanical. without prior written permission of CADD Centre Training Services Private Limited. All other brand names and trademarks used in this material belong to their respective companies. . CADD® CENTRE eY IC----- 1> D T CAOO CENTRE All the above logos are Trademarks of CADD Centre Training Services Pvt. may not be reproduced.. Ltd. . .Contents What is GD& T7 1 Machining Flowchart 1 N~cessity of Dimensional Tolerance 2 Tolerance Dimensioning 2 Deviation 5 Fits between Mating Parts 5 System of Fits 7 Geometric Dimensioning and Tolerance (GD&T) System-ASME Y14.5M-1994 9 Terms and Definitions 11 Maximum Material Condition (MMC) 13 GD&T Rules 15 Datums 16 GD& T Symbols and Modifiers 20 . .--.f' .. C) .. • The first step is conceptual development! product design (the design stage). and processes. GDEtTenables scientific tolerance stack-up analysis.3 (C) 027±0. tools.1: A GDftT Encoded Drawing Machining Flowchart Let us consider the steps involved in creating a mechanical device to solve a given problem. Z(A. ========~== CADD® CENTRE . and encoding the function of each feature of a part. national and ISO standards.B.5@IAIB®lcl 1_L'¢0'5®'A' T DATUM FEATURE A 1 1 (B) EXTENSION LINE LEADER FEATURE CONTROL FRAME Fig 1. BASIC DIMENSION Y AXIS OF DATUM REFERENCE FRAME (A. It consists of concepts.C) X(A.3 1-$-1¢0.B. • Draft !detail the plans for each part (the drawing stage) • Then the individual parts are machined.-2~IA~I~B®~S1 018±0. rules.GD&T II Geometric Dimensioning & Tolerancing What is Geometric Dimensioning & Tolerancing? Geometric Dimensioning EtTolerancing (GDEtT)is a symbolic language for researching. finally the device is assembled.B.C) - ill}--L-----4---~--+-------------~-~I~~~1~0. • Next we layout an assembly plan. In addition to enabling unambiguous decoding to communicate design intent to manufacturing and quality assurance.. and is therefore in a position to absolutely guarantee the assemble ability of in-tolerance mating parts.which are described in various military. and are set forth in this document in abbreviated form. refining. 623. or anywhere between these limit dimensions.627 or 1.e. In setting up machine . i. the dimensional tolerance is decided at the design stage and a Machinist must take care to apply the required dimensional tolerance and to ensure that discrepancies are not introduced as a result of poor workmanship of measuring techniques. Tolerance Dimensioning Tolerance is the total amount that a specific dimension is permitted to vary. in adjusting the tool and work piece on the machine. • It is impossible for an operator to make perfect settings.2: Machining flowchart Necessity of Dimensional Tolerance • It is almost impossible (and sometimes uneconomical) to maintain the strict degree of accuracy due to inevitable inaccuracy of manufacturing methods.625 ± . • Due to interchangeability! mass production.002 means that the manufactured part may be 1.. some errors are likely to creep in.II GD&T Machining ~ (comPletion) Fig 1. Usually. Tolerance may be specified in 3 places: • Directly on (with) the specified dimension • In a genera I note • In title block (tolerance block) For example a dimension given as 1. It is the difference between the maximum and the minimum limits for the dimension. To accommodate this. CADD® CENTRE ---=========== . it is normal to display measurements with a plus or minus (+/-l tolerance which allows for some margin of above errors.. The tolerance is a compromise between accuracy required for proper functioning and the ability to economically produce this accuracy. 98 . In fig.00 ~:g~III II Bilateral Tolerance 1. would be 1. Min Limit: It is defined as the minimum permissible size for a given basic size. In fig.Dia29.05 1.05 III • Equal Bilateral Tolerance 1. the min limit for the basic size of Dia30 is = Dia30 .05 III II Plus Limits. Basic Size or Basic dimension: It is the theoretical size from which limits of size are derived by the application of allowances and tolerances. which is 11/4".00 ~:g~ III II Unilateral Plus Tolerance 1. 1 Lines .GD&T II Expressing Tolerance 1. Max Limit: It is defined as the maximum permissible size for a given basic size.035 .Key terms Nominal Size: It is the designation used for general identification and is usually expressed in common fractions. --=--====--=--=--==== CADD® CENTRE . Actual Size: is the measured size of the finished part.00 ± . 1 Lines Unilateral Bilateral Fig 1.2Smm.98 III II Plus Limits.035mm.215 = Dia29. the max limit for the basic size of Dia30 is = Dia30 + 0. For Ex..98 -1.035 = Dia30. The difference between the max and min limits of a basic size are called tolerance.0.00 ~:gg III • Unilateral Minus Tolerance 1. 2 Lines III II 1. the tolerance is = Dia30. In the previous figure. Limits: The two extreme permissible sizes between which the actual size lines are called limits. 2 Lines .05 .05 III II Minus Limits.785 = 0. the nominal size of both hole and shaft. In fig.98 Minus Limits.785mm. Tolerance: It is defined as the amount of variation permitted to a basic size.25" in a decimal system of dimensioning.3: Expressing i'o/erancing Tolerance definition . Grades of tolerance: In a standardized system of limits and fits. Min. .. size ------t~1 Max. size ---. ~-.Basic Shaft Zero Line -. the actual shaft and the max shaft are aligned at the bottom and a straight line.. called zero line is drawn through the top generator of the basic shaft as shown in fig. ~-. - ... group of tolerance are considered as corresponding to the same level of accuracy for all basic sizes. Actual Deviation: It is the algebraic difference b/w the actual measured size and the corresponding basic size.. the basic shaft. to indicate the deviations graphically. Fundamental Deviation: It is that one of the two deviations which is conventionally chosen to define the position of the tolerance zone in relation to the zero line.. deviations above this line will be positive and below it will be negative. a GD&T Deviation: is the difference between the basic size and the hole or shaft size. This is called zero Line because the deviations at the basic size will be zero.. the min shaft. Lower Deviation: is the difference between the basic size and the minimum permitted size of the part. Upper Deviation: is the difference between the basic size and the permitted maximum size of the part. When the zero line is drawn horizontally. Tolerance zone: The zone bounded by the upper and lower limits of the basic size.Basic Hole International tolerance grade Fundamental deviation cl.. Zero Line: Since the deviations are measured from the basic size.4: Tolerance definition CADD® CENTRE =========== ------.-' Fig 1. It is designated by EI for hole 8: ei for the shaft. Lower deviation: Similarly. it is the difference of dimension between the minimum possible size of the component and its nominal size. For that matter. it refers to the difference between minimum size of the hole 8: the maximum size of the shaft.GD&T II Deviation It is defined as the algebraic difference between a size 8: corresponding basic size. it refers to the difference between maximum size of the hole 8: the minimum size of the shaft. i. It is a positive quantity when the minimum limit of size is greater than the basic size and negative quantity when the minimum limit of size is less tha n basic size. ZERO LINE Deviation <EI> SHAFT (lower limit) Diameter Basic Size -cei» (upper limit) <es> Fig 1. either of the deviations may be considered. it refers to the difference between minimum size of the hole 8: the maximum size of the shaft. Fits between Mating Parts Fit is the general term used to signify the range of tightness or looseness that may result from the application of a specific combination of allowances and tolerances in mating parts. it refers to the difference between maximum size of the hole 8: the minimum size of the shaft. It is a positive quantity when the maximum limit of size is greater than the basic size and negative quantity when the maximum limit of size is less than basic size.e. i. =========== CADD® CENTRE . Maximum Clearance: in a clearance I transition fit. Fundamental deviation: It defines the location of the tolerance zone with respect to the nominal size. Maximum Interference: in a Interference I transition fit.5: Deviation Upper deviation: It is the difference of dimension between the maximum possible size of the component and its basic size. it is designated by ESfor hole 8: es for the shaft. Minimum Interference: in a Interference fit. Minimum Clearance: in a clearance fit.e. the smallest shaft 1.II GD&T There are three types of fits between parts: o Clearance Fit In clearance fit an internal member fits in an external member (as a shaft in a hole) and always leaves a space or clearance betwr _.003" to spare.6: Clearance fit e Interference Fit In interference fit the internal member is larger than the external member such that there is always an actual interference of material.2509" will have to be forced into the smallest hole.. 1.ooor Under maximum material conditions the interference would be 0.2r:-t- ""'1. This interference is the allowance..L_ Fig 1. 1. But the largest shaft. so that there is an actual interference of metal amounting to at least o. and in an interference fit it is always negative.0019".2500" with an interference of metal of 0. with 0. (0) iNTERFERENCE FIT e Transition Fit Transition fit result in either a clearance or interference condition.2506".2506". In the figure below. CENTRE ~ ..2513" and the la rgest hole is 1.2503 t .009': dl._L'_ .2503" will fit in the largest hole 1.__ __ ~ d (b) TRANSITION FIT CADDO ~ . The smallest shaft is 1. FIT Fig 1. Ha/f7 Close Running: For accurate location and moderate speeds and journal pressures. H7/n6 Locational Transition: Fit for more accurate location where greater interference is permissible. Medium Drive: Fit for ordinary steel parts or shrink fits on light sections. Locational Transition: Fit for accurate location. H7/g6 Sliding: Fit not intended to run freely. a compromise between clearance and H7/k6 interference. and to locate accurately.502 .f " .( . but to turn and move freely.495~- -r- (0) BASIC HOLE.498_c=:2_ . When the lower deviation of the hole is zero. but without special bore pressure requirements.. which is taken as the base for computing all other limit dimensions. or heavy journal H9/d9 pressures.9: Hole Basis System CADD® CENTRE {. the tightest fit usable H7/s6 with cast iron. but can be freely H7/h6 assembled and disassembled. high running speeds. Locationallnterference: Fit for parts requiring rigidity and alignment with prime accuracy of H7/p6 location. the minimum limit of the hole is equal to its basic size.(~ . • .1 GD&T II H11/c11 Loose Running: For wide commercial tolerances on external members. Force: Fit suitable for parts which can be highly stressed or for shrink fits where the heavy H7/u6 pressing forces required are impractical. System of Fits Two types of systems used to obtain various types of fits: e Hole Basis System In this system the different types of fits are obtained by associating shafts of varying limit dimensions with a single hole.500 ¢. j_ ¢. Free Running: For large temperature variations. whose lower deviation is zero. Locational Clearance: Fit provides snug fit for locating stationary parts. For fits in precision and general engineering ITll to 1T16. This grade identifies what tolerances a given process can produce for a given dimension. making the minimum hole as 0.II GD&T In the above figure • The minimum size of the hole 0.002" and 0.499': IT Grade IT Grade refers to the International Tolerance Grade of an industrial process defined in ISO286 implements 20 IT tolerance. the maximum limit of the shaft is equal to its basic size.For production of gauges and measuring instruments IT5 to IT12 .495': o Shaft Basis System In this system the different types of fits are obtained by associating holes of varying limit dimensions with a single shaft.10: Shaft Basis System • The maximum size of the shaft 0. When the upper deviation of the shaft is zero.505 )U.502" and the minimum shaft of 0.002" is decided on and subtracted from the basic hole size. which is taken as the base for computing all other limit dimensions. whose upper deviation is zero.003" and 0.502': • Tolerances of 0.498" • Tolerances of 0. _L_/~ j_ n(.002" is decided on and added to the basic shaft size.500" is taken as the basic size.499~ ~/~ '(b) BASIC SHAFT FIT Fig 1.For structures ITll to 1T18. • An allowance of 0.505" and the minimum shaft of 0.For specification of limit deviations of non-tolerated dimensions CADD~ CENTRE ~====~====~= .For production of semi-products 1T16to IT18 .500~_ )U.003" respectively are applied to the hole and shaft to obtain the maximum hole of 0.001" respectively are applied to the hole and shaft to obtain the maximum hole of 0. making the maximum shaft as 0. Field of use of individual tolerances of the system ISO: ITOl to IT6 .500" is taken as the basic size. • An allowance of 0.502 n(. 5M-1994 GD&T is an international language that is used on engineering drawings to accurately describe a part. we assume all 4 legs will be cut to length the same time. I Ii 20±1 _j Fig 1.11: Machining process associated witt) tolerance grades Geometric Dimensioning and Tolerance (GD&T)System-ASME Y14. Consider the following example: Consider a table.12: Tuble with dimensions applied =========== CADD® CENTRE . Given table Height. they must carefully consider the fit and function of each feature of any part. definition & conventions. GD&T encourage a dimensional philosophy called "FUNCTIONAL DIMENSIONING": functional dimensioning that defines a part based on how it functions in the final product. This language consists of well defined set of symbols. rules. With this the designer can properly apply geometric tolerance.GD&T II IT Grade Fig 1. and tertiary datums For our example. CADD® CENTRE =========== . We can now add an allowed deviation also to the feature 1--1.500±0.18: Part with dimensions Here the tolerance must be shown as applying to the feature being controlled. 00. secondary. surface. angle plates. slot. The size and the location of the feature (cylindrical hole) is specified with basic dimension.000-. shown with details of feature control frame would appear like this.500±0. 00.010 1--1. Like this each controlled feature (hole. the component. Feature control frame has the following: A geometric characteristic symbol A tolerance zone descriptor A tolerance of location A material condition symbol Primary. etc) associated with the basic dimension is given a feature control frame to show a tolerance. and machine tables.17: Datums Some common datum feature simulators are surface plates. shaft. chucks. mandrels. The tolerance that appears in the feature control frame is the allowed deviation from the perfect size or location shown by dimensions. Feature Control Frame: Imagine the control of dimensions of this part shown here.010 Fig 1.000-.m GD&T Datum axis Datum paints measurement Datum planes Origino( measurement Fig 7. -. and the minimum material remains. LMC Symbol Maximum Material Condition (MMC) MMC is that condition of a part or feature which contains the maximum amount of material. and the maximum material remains. e..g.. orientation and/or location and permits additional tolerance as the considered feature departs from its maximum material condkion.. form... minimum size hole. or a maximum size shaft The maximum material principle takes into account the mutual dependence of tolerances of size. MMCSymbol Least Material Condition is the condition in which a feature of size contains the least amount of material everywhere within the stated limits of size.030@ I A I B lei Fig 1. Assembly clearance is increased if the actual sizes of the mating features are finished away from their MMC. They can be either Maximum material condition or least material condition. This means that the tolerance is at the extreme that would result if too much material was cut off. ~ ===~~====== CADD® CENTRE ~ . and if any errors of form or position are less than that called for by any geometrical control. modifiers can be added to change their meanings.....19: Feature control frame Material Condition: To overcome shortcomings in symbols.GD&T m 1-$-1 ¢O. This means that the tolerance is at the extreme that would result if too little material was cut off.____ Maximum Material Condition is the condition in which a feature of size contains the maximum amount of material everywhere within the stated limits of size. Or Constant value outer locus 8: constant value inner locus values are derived o 0. 1 ".1 Positional zone atMMC 030. profile of a surface.20: virtuot condition ~ •.0 0.1 Positional zone at MMC 030 Virtual condition (Inner boundary) VIRTUAL CONDITION BOUNDARY The M M C modifier applied to the position tolerance implies. VL tc~I"'o dition A constant boundary generated by the collective effects of a size features specified MMC/LMC 8: the geometric tolerance for that material condition. profile of a line. It can never be applied to a plane. run-out. that a virtual condition is defined for the features and the calculations are Pin in Plate 1 done with the M M C limit of size. roundness. Boundary Hole in Plate 2 Virtual condition for hole >= Virtual condition for pin Fig 7. surface.III GD&T Its application is restricted to those features whose size is specified by tolerance dimensions incorporating an axis or median plane. The characteristics to which the maximum material condition concept cannot be applied are as follows: flatness. cylindricity.tf . or line on a surface.1 MMC size of feature . ..0st. 0 0.5 This Is an Imaginary Hole '" .0}O' £7 l.s'02 :$ o [ J05102 :$ l.9 milleters + 0 0._----.. -E ! J0.001 MANUfACTURED SIZE OUT-Of·STRAIGHTNESS MANUFACTURED SIZE OUT OF ROUNDNESS CADD" CENTRE .0st.. the limits of size of an Individual future prescribe the extent to which variation in its geometric form as well as sizes are allowed.003 I r0.1 boundary outside Itself GD&T Rules ul.W· Individual Feature of Size/Perfect form at MMC/Envelope rule: Where only a tolerance of size is specified.005 -c::r:?3.9 Condition o Virtual Condition for internal feature Virtual Condition: Hole MMC 0 29. .4 Pin '" ~ Pin Virtual o 26. will maintain the hole '+~-""!<o'~-ViI·tual Condition Hole Virtual 0 29.OO1 ~~($ ()()6 ~ -E t I ~($ l.001 3.' . .sb3 :$ tOOl -F l. GD&T o Virtual Condition for external feature Q . £7 -E l.~ ~$.•• The virtual condition O~ Virtual Condition: of the pin shown here Is thus an envelop of diameter Pin MMC 0 26.4 envelope in space and --.oo. .OO1 .5 26. ~ ~$ 00 I~$ \ I t. £7 -( I tooo j." -F::f?-t~-r. =t . 00:± .002 1.05 (LMC) Fig 1.-----------. datum reference.002 RFS Fig 1. Therefore it is necessaryto establish a method of simulating the theoretical reference frame from the actual features of the part.22: GOaT Rule2 Datums Datum are theoretical. with respect to the individual tolerance.O.1982) . CADD® CENTRE -=--=-=--===-=---=--=== .1 1.1 AT 0 6. MMC/LMC must be specified on the drawing where it is required. It consists of: • Axes • Planes These elements exist within a frame work of three mutually perpendicular intersecting planes known as datum reference frames.5M .002 1.000 .95 (MMC) TWO POINT CHECKS 2X 010±O.002 . or both.001 .': FULL FORM CHECK AT 0 5. where no modifying symbol is specified.21: GDEtT Rule I Rule #2 RFSapplies. ~ .002 .999 .002 PRODUCED SIZE TOLERANCE (lOmm) 1.002 Symbol for RFS(past practice from Y14.998 . The datum reference frame is a virtual reference frame that does not exist on the part actually.II GD&T 06±O. 0 1 l. I I I I I I XY I / I I / I I / I I / I ~ "v I .23: Datums . to restrict motion of the datum reference frame..24: Datum Simulation CADD~ CENTRE ..f'ltior Met-} od The simulation is accomplished by positioning specifically identified features in contact with appropriate datum simulators. y Datum axis Datum '1 Datum planes origin of measurement Fig 1. GD&T III Datum Reference Frame y II r------------.-----------~ I X I I I I I I y : / xz / I I I ~~/- Z ----------_/ Fig 1. These specifically identified features are called as datum features. in a stated order of precedence. 25: DOF Let us the part in a simulated datum reference frame. y " Fig 1. the remaining single degree of freedom is also eliminated and this provides a positive part orientation for any manufacturing or inspection procedure required.~~~-+-+--CD+-~- r® z /.--- . ~G) Fig /.. Now bringing in a secondary datum plane we find that more degreesof freedom are eliminated. Now bringing the part in contact with a tertiary datum plane. . Establishing a primary datum reference frame. we see two rotational and one linear degree of freedom are eliminated.26: Dotum Simutation CADD~ CENTRE =========== -------. GD&T A free floating part has six degrees of freedom: • Rotation about X • 'Rotation about Y • Rotation about Z • Translation about X • Translation about Y • Translation about Z y / ® . its function in assembly or its rough or warped surfaces. a line or lines. Simulated Datum Feature . The portion may be designated as a point or points. or an area or areas.28: Datum Targets . which is used to establish the location of a datum is called as datum feature. Now consider a part.. i Fig 1. where appropriate to specify tolerances of form to them. GD&T--------------------------------------. it may be necessary. As datum features are subject to manufacturing errors and variations. Surface Plate Fig 1. Sometimes due to the configuration of a part. it becomes desirable to use only a portion of the surface as a datum. a real feature of a part (in this case a surface). This real surface is called as simulated datum features.The areas may be defined as any shape that is appropriate. line or point that may be used for datum referencing.27: Datum Feature Datum Targets Datum targets are specific portions of a surface. II a tu 1 L'ea~ure Consider a surface plate having a real feature of adequately precise form contacting the datum features. The use of a dashed radial line indicates that the datum target is on the far (hidden) surface.!!J1 Required) CONCENTRICITY 0 -- LOCATION POSITION ~ SYMMETRY - Fig 1. GD&T Symbols and Modifiers ASME follows fourteen geometric symbols and the modifiers as given in the table. The datum target symbol consists of a circle cut in to two halves. 010 Al -'lr----r. lines and areas on datum features are designated on the drawing by means of a datum target symbol.__--.30: Geometric Symbols . The use of solid radial line indicates that the datum target is on the rear surface.t (Datum RUNOUT Reference TOTAL RUNOUT .L ORIENTATION ANGULARITY L PARALLELISM II RELATED FEATURES CIRCULAR RUNOUT . or RELATED PROFILE FEATURES SURFACE PROFILE 0 PERPENDICULARIT ../ @ ® Fig 1. The top tier contains the target area size that can be placed either internally or externally as shown. The lower tier contains a datum identifying letter with a target number.. GD&T Datum Target symbols Points.29: Datum Target Symbols The symbol is placed outside the part outline with a radical (leader) line directed to the target. TYPE OF TYPE OF CHARACTERISTICS SYMBOL FEATURES TOLERANCE FLATNESS 0 INDIVIDUAL STRAIGTNESS (NO Datum FORM Reference) CIRCULARITY 0 CYLINDRICITY 1:/ INDIVIDUAL LINE PROFILE r-. .... Fig 1.f • of": .r GD&T Ell TERM SYMBOL AT MAXIMUM MATERIAL CONDITION @ AT LEA8T MATERIAL CONDInON © PROJECTED TOLERANCE ZONE ® Modifying symbols FREE STATE ® TANOENT PLANE (f) DIAMETER ¢ SPHERICAL DIAMETER s¢ RADIUS R SPHeRICAL RADIUS SR CONTROLLED RADIUS CR Additional Symbols REFERENCE () ARC L£NOTH .32: Profile of a line CADD® CENTRE . STATISTICAL TOLERANCE (ill BETWEEN +-+ Fig 1.....31: Modifiers Profile tolerances o Profile of a Line A uniform two dimensional zone limited by two parallel zone lines extending along the length of a feature. The amount of deviation that is allowed for a surface to float within a certain dimensional range while maintaining the shape or form of each line elements that makes up that surface. . inclined at a specified basic angle in which the surface. or center plane of the feature must lie. ft" .. Fig 1. axis.33: Profile of a surface A uniform three dimensional zone contained between two envelope surfaces separated by the tolerance zone across the entire length of a surface. Orientation tolerances o Angularity L The distance between two parallel planes.m GD&T o Profile of a Surface It is the amount of deviation that is allowed for a surface.fro . It requires that all points on a specified feature must form an angle with a datum./' .34: Angularity CADD®============ CENTRE l . Fig 1. ..u......J/...-/ /.. All points on a surface are to be parallel to a given datum.-------.../.."""/."""/"'""' 0. ~ ~I......!-../....""" ..""'/. or line which is exactly at 90 degrees with respect to a datum plane or axis... ~ ~ ~ ~ ~ ~ /. axis.."""/./ /. GD&T ---------------------------------------. : ~.....01 Tolerance Zone 1 1.35: Perpendicularity o Parallelism II The condition of a surface or axis which is equidistant at all points from a datum of reference. Fig 1.-/... It requires that all points on a specified feature must be perpendicular with a datum. II o Perpendicularity j_ The condition of a surface./..-.. median plane.. """""""/.36: Parallelism ./..003 Tolerance Zone Fig 1... within a specified tolerance. _[0. A Fig 1.axis coincides with the datum axis and within which all cross- sectional axes of the feature being controlled must lie.500 4X00. 1-$-1 ¢o.38: Concentricity CADD® CENTRE =========== .37: True position o Concentricity A cylindrical tolerance zone whose .o30@1 1 1c 1 0 B 1. It is also capable of confining a surface or surfaces within or outside of a boundary known as virtual condition. Concentricity is a geometric control of the median points of all diametricallv- opposed elements of a figure of revolution. center plane or axis of a feature of size. axis.010 Fig 1. or center plane of a feature of size is permitted to vary from its true (theoretically exact) position. A position tolerance generates a tolerance zone that confines the center.2000±0.II GD&T Locational tolerances o Tru Position A zone within which the center. (Note: Concentricity is very expensive and time- consuming to measure. 02 Tolerance Zone [ Fig 1..J 1-1 . --.--------+. 2.005 1. . . __j . 0.40: Circular runout ---------..001 L Fig 1. . GD&T--------------------------------------- o Symmetry Symmetry is that condition where the median points of all opposed or correspondingly located elements of two or more feature surfaces are congruent with the axis or center plane of datum feature. -11 .005 -.r 1...000±.0051 ciA 1 .39: Symmetry Runout tolerances o Circular Runout A composite tolerance used to control the relationship of one or more features of a part to a datum axis during a full 360 degree rotation about the datum axis..005 .000±..001 -. - ..375±.1 1..700±..___.875±. 1-=-1. t -------.' . -_-. GD&T o Total Runout All surface elements across the entire surface of the part must be within the runout tolerance.I:" .41: Total runout Form tolerances o Flatness o A two dimensional tolerance zone defined by two parallel planes within which the entire surface must lie. Tolerance Zone Fig 1. Basically all the surface elements are constrained to lie within two parallel planes.0011 r Tolerancezo: ~:~ _ t '--------'==r:f Fig 1. separated by the tolera nee.42: Hotness o Straightness A condition where an element of a surface or an axis is a straight line. - s . One of the surface elements is constrained to lie within two parallel surface planes separated by the tolerance. 1010. the part is acceptable. CADD® CENTRE =========== . This means that if any line across the surface is within two parallel lines. 45: Cylindricily ========---=== CADD~ CENTRE ------_. cone. It is an extension to circularity that specifies the tolerance along the cylinder. cone) or passing through a common center (sphere) are equidistant from the axis of the center.0011 -+-.. -- .001 L_ _ Fig 1.44: Circularity o Cylindricity A condition on a surface of revolution in which all points of the surface are equidistant from a common axis.43: Straightness o Circularity o A condition on a surface of revolution (cylinder. straightness and taper.001 Tolerance Zone Fig 1. It is a 2-D surface form control. L' 1:11 0. GD&T iii 1-10. 0.0011 I Tolerance Zone 0. sphere) where all points of the surface intersected by any plane perpendicular to a common axis (cylinder. It is a 3-D form control which controls roundness (circularity).----~.01 Tolerance Zone ------- -$ Fig 1. All of the points on a cylindrical surface are constrained to lie within two circles.$ 0. ---- . -. GD&T Index A IT5 to ITl2 8 Actual Deviation 4 IT11 to ITl6 8 Actual Size 3 ITl 1 to ITl 8 8 Angularity 22 IT16 to ITl 8 8 IT Grade 8 B L Basic Size or Basic dimension 3 LeastMaterial Condition 13 C Limits 3 Locational tolerances 24 Circularity 27 Lower deviation 5 Circular Runout 25 Lower Deviation 4 Clearance Fit 6 Concentricity 24 M Cylindricity 27 Machining Flowchart 1 o Material Condition 13 Maximum Clearance 5 Datum Feature 19 Maximum Interference 5 Datums 11 Maximum Material Condition 13 Datum Targets 19 Maximum Material Condition (MMC) 13 Datum Target symbols 20 Max Limit 3 Deviation 4 Minimum Cledrance 5 Minimum Interference 5 E Min Limit 3 Expressing Tolerance 3 N F Necessity of Dimensional Tolerance 2 Feature 11 Nominal Size 3 Feature of Size 1 1 Fits between Mating Parts 5 o Flatness 26 Orientation tolerances 22 Form tolerances 26 Fundamental deviation 5 p Fundamental Deviation 4 Parallelism 23 G Perpendicularity 23 Profile of a Line 21 GD& T Rules 15 Profile of a Surface 22 GD&T Symbols and Modifiers 20 Profile tolerances 21 Grades of tolerance 4 R H Rule # 1 15 Hole Basis System 7 Rule #2 16 Runouttolerances 25 Interference Fit 6 ITO1 to IT6 8 CADD® CENTRE ----. Key terms 3 Tolerance Dimensioning 2 Tolerance zone 4 Total Runout 26 Transition Fit 6 True Position 24 U Upper deviation 5 Upper Deviation 4 V Virtual Condition 14 Virtual Condition for external feature 15 Virtual Condition for internal feature 15 Z Zero Line 4 II . GD&T II S Shaft Basis System 8 Simulation Method 17 Straightness 26 Symmetry 25 System of Fits 7 T Termsand Definitions 1 1 Tolerance 3 Tolerance definition . we ensure that you get world class reference guides and instructors..4596 6100 CENTRE www.- . Office No: BC & 8g. Register to learn from the best! Master Diploma and Professional Programs offered in: ~ Mechanical Product Design ~ Architectural Design ~ Electrical CADD ~ Mechanical Product Analysis ~ Structural Design ~ Project Planning & Management ~ Aerospace Design ~ Building Design ~ Automotive Design ~ Land Survey & Transportation Design t #91. Chennai . Mylapore.cadctcentreglobal. learn from experts! As Asia's biggest training institute. 25 countries.caddcentre. Radhakrishnan-Salai. 1MiUion students trained. 28 years. Dr. Driving Digital Designs! .600 004.com f www. CADD®· Plil: 044 . GEEGEECrystal. Our Internal Training Academy constantly monitors training methods and our instructors are tested & recertified at regular intervals. Come. 8t~Floor.com . /1 . CADD® CENTRE 1IIIIIUIIIIIIIII161 '1IIIIIi~l)ilglillliniilIil V341605-RB063-C02518 [I . Customer Notification QUALITY ~IRST .